Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Communication networks may require Quality-of-Service (QoS) provisioning for forwarding of data between routers (herein referred to as “nodes”) interconnected via communication channels. A process known as QoS routing may be used to find a path or route through a network of interconnected nodes that may meet minimum QoS requirements associated with data to be forwarded through the network of interconnected nodes. QoS routing may be based on a QoS state of separate outgoing links of communication channels coupling nodes of the network. The QoS state may indicate a capability of an outgoing link to meet at least minimum QoS requirements. For example, a minimum QoS requirement may include a minimum threshold for available bandwidth at an outgoing link of a communication channel coupled to a node.
Various QoS routing schemes have been developed that depend on timely awareness of QoS link states for the outgoing links included in a given QoS route through a network of nodes. These QoS routing schemes may allow nodes to forward packets of data according to a QoS link state (e.g., available bandwidth) at each hop or outgoing link of a node along the QoS route that may satisfy at least a minimum end-to-end QoS requirement for the QoS route. Dissemination mechanisms to convey timely or updated link state information to interconnected nodes may include flooding link-states advertisement (LSA) packets. Flooding LSA packets may include each node sending or forwarding its own LSA packet and forwarding those LSA packets created by other nodes until all nodes in the network have a current or updated knowledge of each node's QoS link states for their respective outgoing links. Once nodes receive updates of the QoS link states, the QoS route may be updated and/or changed to reflect the current QoS link states.
Dissemination mechanisms based on flooding LSA packets may generate a significant dissemination overhead. The dissemination overhead may continue to increase as additional minimum QoS requirements (e.g., packet loss rates, delay, security, etc.) may be added to forward packets of data via a QoS route. Also, link state information may become stale or out-of-date by the time all nodes in a network receive an update LSA packet via flooding. This staleness may be due to network congestion at the time of the flooding or due to other types of network performance issues (e.g., broken/malfunctioning communication channels). Further, to minimize the impacts of dissemination overhead on the performance of the network, update frequencies may be extended to time intervals of 30 minutes or more. However, extended update intervals may also lead to stale or out-of-date link state information.